Electrical connector for use in coupling two printed boards

Abstract: Disclosed is an improved electric connector assembly for use in coupling two printed boards. The height of such assembly is reduced yet a good effective length of contact beam and increased distance between the soldering tails of the opposite terminals is assured. Each female terminal (9a, 9b) is composed of a horizontal base (10), a contact beam (13) rising from one end of the horizontal base and having a contact (12) near its top end. A transition (15) descends from the other end of the horizontal base, and a soldering tail (16) horizontally extends from the transition. The female terminals are attached to opposite side walls (3, 4) of their housing with their horizontal bases partly embedded in the opposite side walls.

Description: Field of the Invention The present invention relates to an electrical connector according to the preamble of claim 1. Description of the Prior Art An electrical connector according to the preamble of claim 1 is known from US-A-5,167,528 or EP-A 0 567 007 A3. Each terminal of such an electrical connector comprises a vertical beam and a horizontal leg. The vertical beam extends through the base of the housing, whereas the horizontal leg includes the tail portion to be soldered to an electrical circuit of a circuit board. During the soldering process of such a connector, the solder will, by adhesion force, travel upwards along the tail portion and further along the vertical beam. Once the solder has reached the point where the vertical beam protrudes the housing, it begins to spread along the bottom of the housing and may cause short circuits with neighbouring terminals. Also, solder that collects on the base of the housing is not available for the soldering joint between the terminal and the circuit board, rendering the connection incomplete and unreliable. Japanese Patent Application Public Disclosure No. 5-144498 discloses such an electric connector assembly of reduced height. As seen from Fig. 19 herein, its female part has a pair of female terminals 2' arranged in opposite relationship and fitted in its housing. Each female terminal is composed of a vertical base section 3', a soldering tail 61 horizontally extending from one end of the vertical base section 3' and a contact 5' rising up from the other end of the vertical base section 3'. The opposite female terminals 2' are embedded by their base sections 3' in the floor 4' of the housing 1' of the female part, allowing their soldering tails 61 to lie under the bottom 7' of the housing 1', and at the same time, allowing their contacts 5' to remain in the terminal accommodating space in the housing 1'. As seen from the drawing, there are no recesses made in the bottom 7' of the housing 1' particularly in the vicinities of the transient parts from the soldering tails 6' to the vertical base section 3' of the opposite female terminals 2'. The male part of the conventional electric connector has a pair of male terminals 10' arranged in opposite relationship and fitted in the housing 9'. Each male terminal 10' is composed of a vertical contact section, a soldering tail 13' horizontally extending from one end of the vertical contact section, a slanted transient section extending from the other end of the vertical contact section, and a vertical holding section 11' extending from the slanted transient section. The vertical holding section 11' of the opposite male terminals 10' are press fitted in the opposite slots 12' of the center leg of the housing 9' of the male part, allowing the soldering tails 13' to be extended laterally outward. The prior art electric connector has following defects: (1) as the vertical extension of each female terminal 2' rises from the floor 4' of the female housing 1', the rising extension must be reduced with the reduction of connector's height until its resiliency is lowered, causing an adverse effect on the making of electric contact; (2) as each female terminal has a simple bending at the transient from the soldering tail to the vertical contact section, the distance L' between the opposite soldering tails 6' is reduced with reduction of connector's height accompanying reduction of lateral size so that it may be very difficult to arrange on a printed board, conductors apart enough to permit such conductors to be connected to the closest soldering tails; and (3) there are no recesses made on the bottom 7' of the housing 1' particularly in the vicinities of the transients 8' from the soldering tails 6' to the vertical contact sections 3', and therefore the soldering of the transients 8' of the female terminals 2' to conductors on the printed board is so difficult that there is a concern about incomplete soldering. As for the male part, the vertical holding section 11' of the opposite male terminals 10' are press fitted in the opposite slots 12' of the center leg of the housing 9' of the male part, stressing the opposite slots 12' and potentially causing the undesired buckling of the male part housing apart from the female part housing. This tendency is liable to appear increasingly with the decrease of connector's height. Summary of the Invention One object of the present invention is to provide an electric connector for use in coupling two printed boards, which electric connector structure meets the requirement of reduction of height, yet still assuring: first, a good resilient length of contact section in terminals; second, a good distance between the opposite soldering tails; third, no fear of permitting the rise of flux up to the terminal holding section at the time of soldering; fourth, a good solder joint at each soldering tail; fifth, no buckling of the male part housing apart from the female part housing; and sixth, reliable, high durability locking of the male and female parts. The invention is defined in claim 1. Such an electrical connector for use in coupling two printed boards comprising a male part having a plurality of pairs of male terminals longitudinally arranged and attached to its housing, and a female part having a plurality of pairs of female terminals longitudinally arranged and attached to its housing, the contacts of said male terminals being adapted to be put in contact with the corresponding contacts of said female terminals when said male and female parts are mated together, is improved in that: each of said female terminals is composed of a horizontal base, a contact beam rising from one end of said horizontal base and having a contact near its top end, a descent descending from the other end of said horizontal base, and a soldering tail horizontally extending from said descent, said female terminals being attached to the opposite side walls of the housing of the female part with their horizontal bases partly embedded in the opposite side walls, allowing their soldering tails to lie under the bottom of the housing, and at the same time, allowing their contact beams to be extended in the terminal accommodating space in which said male terminals are to be inserted when said male and female parts are mated together. The bottom of the housing has a recess made in the vicinity of the transient portion from the descent to soldering tail of each female terminal. Each of said male terminals may be composed of a base, a contact beam rising from one end of said base and having a first catch at its top end, a second catch descending from the other end of said base, and a soldering tail horizontally extending from said second catch, said male terminals being attached to the opposite side walls of the housing of the male part with their first and second catches embedded in the top ends and floors of the opposite side walls, allowing their soldering tails to lie under the bottom of the housing, and at the same time, allowing their contact beams to extend in the terminal accommodating space defined in said female part when said male and female parts are mated together. The bottom of the housing has a recess made in the vicinity of the transient portion from the second catch to soldering tail of each male terminal. The housing of said female part may have an elongated terminal mount in the space defined by its opposite side walls and opposite end walls, said elongated terminal mount having a latch member formed in the center of either opposite end wall, and the housing of said male part may have a catch member formed in the center of either opposite end wall, thereby permitting the housing of said female part and the housing of said male part to be locked when mated together. With such arrangement as described above a good resilient length of contact section in each female terminal is assured by the resiliency provided by the horizontal base partly embedded in each side wall of the housing. Also, a good distance is assured between the opposite soldering tails because of additional horizontal base lengths. In addition, at the time of soldering there is no fear of permitting the rising of flux up to the terminal holding sections which are provided in the form of horizontal bases embedded in the opposite side walls because such terminal holding sections are not upright from the printed board as is the case with the conventional electric connector as shown in Fig. 19. The soldering can be effected with ease thanks to the recess made on the housing bottom near each soldering tail-to-descent transient part of the female terminal. No buckling of the male part housing can be caused because no stress appearing in the insert-molding of male terminals, different from the press-fitting of male terminals in the housing. Also, the soldering can be effected with ease thanks to the recess made on the housing bottom near each soldering tail-to-contact beam transient of the male terminal. Finally, the reliable, high-durable jocking of the male and female parts is assured because the locks and provided inside, not exposed directly to undesired impacts from the outside. Brief Description of the Drawings Other objects and advantages of the present invention will be understood from the following description of electric connectors according to preferred embodiments of the present invention, which embodiments are shown in accompanying drawings: Figure 1 is a plane view of a female part of an electric connector of a first embodiment of the present invention; Figure 2 is a right side view of the female part; Figure 3 is a bottom view of the female part; Figure 4 is a front view of the female part; Figure 5 is a plane view of a male part of the electric connector of the first embodiment of the present invention; Figure 6 is a right side view of the male part; Figure 7 is a bottom view of the male part; Figure 8 is a front view of the male part; Figure 9 is a cross section taken along the line X-X in Figure 2 and along the line Y-Y in Figure 6, showing the manner in which the male and female parts are mated together; Figure 10 is an enlarged section showing a female terminal fixed to the housing of the female part; Figure 11 is an enlarged section of a recess made in the bottom of the housing of the female part; Figure 12 is an enlarged section showing a male terminal fixed to the housing of the male part; Figure 13 is a cross section similar to Figure 9, but showing the manner in which the male and female parts of an electric connector according to a second embodiment of the present invention are mated together; Figure 14 is a bottom view of a male part of an electric connector according to a third embodiment of the present invention; Figure 15 is a section taken along the line Z-Z in Figure 14; Figure 16 is a plan view of a female part of an electric connector according to a fourth embodiment of the present invention; Figure 17 is a section taken along the line V-V in Figure 16; Figure 18 is a section partly showing the mating of the female part of Figure 16 and the male part of Figure 14; and Figure 19 is a cross section showing a conventional electric connector. Description of Preferred Embodiment: First, referring to Figures 1 to 4 and Figures 9 to 11, the female part 1 of an electric connector according to the first embodiment is described. The female part 1 has a housing 2 composed of opposite side walls 3 and 4, opposite end walls and a floor 5 together defining a space 6 to accommodate the contacts of the male part of the electric connector. The housing 2 has a center longitudinal projection 7, of which the top surface is used as a vacuum-sucking area 8 for pick and place purposes. the center section 7 is approvimately the same height as the female termianls 9a and 9b. As seen from Figures 1 to 3, a plurality of pairs of stamped and formed female terminals 9a (on left side) and 9b (on right side) are longitudinally arranged at regular intervals in the housing 2. A pair of female terminals are symmetrical in shape, and therefore, only one female terminal 9b is described with reference to Figure 10. Each female terminal is composed of a horizontal base 10, a contact beam 13 rising from one end 11 of the horizontal base 10 and having a curved contact 12 near its top end, an angled descent 15 descending from the other end of the horizontal base 10, and a soldering tail 16 horizontally extending from the descent 15. Such female terminals 9a, 9b are attached to the opposite side walls 3 and 4 of the housing 2 of the female part 1 with their horizontal bases 10 embedded partly (as indicated at 10a) in the opposite side walls 3 and 4 as for instance by insert molding allowing their soldering tails 16 to lie below the bottom 18 of the housing 2, and at the same time, allowing their curved contact beams 13 to be extended in the terminal accommodating space 6 in which the male terminals 39a, 39b are to be inserted when the male and female parts 31 and 1 are mated together. As seen from Figure 9, the exposed portion 10a of each horizontal base 10 is laid on the floor 5. A triangular portion 3' and 4' of each sidewall extends into space 6 towards projetion 7 to help secure the terminal in place. The bottom 18 of the housing 2 has a recess 19 made near the transient portion 17 from the descent 15 to the soldering tail 16 of each female terminal 9a or 9b. A hole 18' is provided to permit the deflectable portion 10b of horizontal base 10 to deflect and to allow the terminal to be supported during the overmolding process used to manufacture the connector. Next, referring to Figures 5 to 8 and Figure 12, the male part 31 of the electric connector according to the first embodiment is described. The male part 31 has a housing 32 composed of opposite side walls 33 and 34, opposite end walls and a floor 35, together defining a space 36 to accommodate the contact beams of the female part of the electric connector. The floor 35 is sufficiently smooth to permit it to be used as a vaccum sucking area for pick and place purposes. As seen from Figure 5 to 8, a plurality of pairs of male terminals 39a (on left side) and 39b (on right side) are longitudinally arranged at regular intervals in the housing 32. A pair of male terminals are symmetrical in shape, and therefore, only one male terminal 39a is described with reference to Figure 12. Each male terminal is composed of a base 40, a contact beam 43 extending from one end 41 of the base 40 and having a first catch 42 at one end, a second catch 45 descending from the other end of the base 40, and a soldering tail 46 horizontally extending from the second catch 45. The exposed surface of the contact beam 43 provides a contact section 48. The male terminals 39a, 39b are attached to the opposite side walls 33 and 34 of the housing 32 of the male part with their first and second catches 42 and 45 embedded in the top ends and floors 35, respecitvely, of the opposite side walls 33 and 34 as for instance by insert molding, allowing their soldering tails 46 to lie under the bottom 49 of the housing 32, and at the same time, allowing their contact beams 43 to extend in the terminal accommodating space 36 defined in the female part 1 when the male and female parts 31 and 1 are mated together. As seen from Figure 12, each contact beam 43 extends along side wall 33 or 34, permitting its exposed surface to be used as contact. The bottom 49 of the housing 32 has a recess 50 made near the transient portion 51 from the second catch to the soldering tail 46 of each male terminal 39a or 39b. The manner in which such electric connector is used is described below. First, the female part 1 is attached to one printed board 21 by soldering the soldering tails 16 of the female terminals 9a and 9b to selected conductors of one printed board 21. As seen from Figure 9, the soldering tails 16 of the opposite female terminals 9a and 9b are separated a relatively long distance 1, thanks to the extra lengths of horizontal bases 10 regardless of the reduction of connector height, thus permitting selected conductors on the printed board to be soldered to the soldering tails 16 with ease. As indicated at 20 in Figure 9, the soldering is effected to the soldering tail-to-descent transient 17 at the recess 19, which facilitates the precision soldering to selected conductors on the printed board. On the other hand the male part 31 is attached to the other printed board 47 by making use of the recesses 50 on the bottom 49 of the housing 35 to solder the soldering tail to second catch transients 51 of the male terminals 39a and 39b to selected conductors of the other printed board 47 with ease and high precision. When the male and female parts are mated together, the contact sections 48 of the opposite male terminals 39a and 39b contact the curved contacts 12 of the opposite female terminals 9a and 9b to make the required electric connections. Even if the contact beams 13 of the opposite female terminals 9a and 9b are reduced with reduction of connector's heights, the lengths 10b of the horizontal bases 10 function as resilient means, thereby adding extra resilience to the shortened contact beams 13 of the opposite female terminals 9a and 9b to assure the sufficient effective length of resilience to permit application of the curved contacts 12 against the contact beams 4 with required contact pressure independent of reduction of connector's height. Figure 13 shows an electric connector according to another embodiment, which is different from the electric connector of Figure 9 only in that the descents 15 stand upright. The so modified electric connector can attain same function and advantage as the electric connector of Figure 9. Finally, referring to Figures 14 to 18, the locking of the male and female parts is described below. The housing 2 of the female part 1 has an elongated terminal mount 60 in the space defined by its opposite side walls 3 and 4 and opposite end walls 61 and 62, as seen from Figures 16 and 17. The elongated terminal mount 60 has a plurality of female terminals 9a and 9b, and the terminal mount has a latch member 55 formed in the center of either or both of opposite end walls 58 and 59. The latch member 55 projects from the free end of resilient J-shaped arm 54 integrally connected to the lower part of the end wall 58, as seen from Figure 17. As seen from Figures 14 and 15, the housing 32 of the male part 31 has a catch member 53 formed in the inside, center of either or both of opposite end walls 56 and 57. In this particular example, the catch member 53 is made in the form of slot. Thus, the housing 2 of the female part 1 and the housing 32 of the male part 1 are locked to each other when mated together. Specifically, when the male part housing 32 is inserted in the female part housing 2, the latch members 55 of the opposite end walls 58 and 59 of the terminal mount 60 of the female part housing 2 fit in the slots 53 on the inside surfaces of the opposite end walls 56 and 57 of the male part housing 32, thereby locking the male part to the female part. The locking is effected inside, and therefore, is insensitive to undesired impacts from the exterior, and accordingly the locking parts are durable.

Claims: An electrical connector (1) comprising: a dielectric housing (2) which includes a pair of spaced apart generally parallel side walls (3, 4), spaced apart generally parallel end walls (61, 62) interconnected thereto, and a housing base (5) including a bottom surface (18), the housing (2) defining an accomodating space (6) for mating along a mating axis with a complementary mating electrical connector (31); a plurality of terminals (9a, 9b) mounted in said dielectric housing (2) so as to extend in said accomodating space (6) and out of said bottom surface (18); each said terminal (9a, 9b) having a cantilevered contact beam (13) extending in said accomodating space (6) generally parallel to said mating axis and having a free end with a contact area (12) for contacting a mating terminal (39a, 39b) of said complementary mating electrical connector (31), a base member (10) extending generally perpendicular to to said mating axis and said contact beam (13) and from which said contact beam (13) extends, a tail portion (16) for interconnecting said terminal (9a, 9b) to an electrical circuit (21) of a circuit member upon which said electrical connector is adapted to be mounted, and a descending portion (15) connected to said tail portion (16) through a transition portion (17) and extending between said tail portion (16) and said base member (10), said base member (10) being arranged in and near said accomodating space (6) and having a deflectable portion (10b) adjacent said contact beam (13) to increase the effective beam length of said female terminal (9a, 9b) and a holding portion (10a) which is supported by said housing base (5) and has a length which is enclosed within said side walls (3, 4) of said housing (2) to retain said terminal (9a, 9b) within said housing wall, characterized in that: said bottom surface (18) has a recess (19) adjacent to said transition portion ( 17 ) so as to facilitate soldering (20) of the terminals (9a, 9b) to said electrical circuit (21), said recess being disposed inwardly of said transition portion (17) . The electrical connector as set forth in claim 1, characterized in that a central projection (7) extends upward from said housing base (5) between said side walls (3, 4) to define said accomodating space (6) as a generally rectangular channel between said central projection (7) and each said side wall (3, 4), each side wall (3, 4) including a securement member (3', 4') which is formed to engage said holding portion (10a) to assist in retaining said female terminal (9a, 9b) within said housing (2). The electrical connector as set forth in claim 1 wherein said housing includes a bottom surface (18) having a recess (19) adjacent the junction (17) of said transition portion (15) and said tail portion extending away from a lower surface of said tail portion. The electric connector set forth in any of claims 1 to 3, characterized in that said electrical connector (1) and said complementary mating electrical connector (31) mate to comprise an assembly for use in coupling two circuit members, said complementary connector (31) having a plurality of pairs of male terminals (39a, 39b) longitudinally arranged and attached to a complementary housing (32), and being adapted to engage corresponding contacts (12) of said terminals (9a, 9b) when said electrical connector (1) and said complementary electrical connector (31) are mated together. The electric connector set forth in claim 4 characterized in that said complementary housing (32) has opposite side walls (33, 34) connected by end walls (56, 57), said side walls and end walls extending from a housing base (35), each of said terminals (39a, 39b) includes a base (40), a contact beam (43) extending from one end (41) of said base (40) and having a first catch (42) at an end thereof, a second catch (45) extending from an other end of said base (40), and a soldering tail (46) extending from said second catch (45), each of said male terminals (39a, 39b) being mounted to one of said side walls (33 and 34) of said complementary housing (32), said first catch (42) of each terminal being embedded in a portion of one of said side walls (33 and 34) spaced from said housing base (35), and said second catch (45) of each terminal being embedded in a portion of said housing base. The electrical connector set forth in claim 5, characterized in that said complementary housing (32) includes a bottom (49) surface having a recess (50) adjacent the junction (51) of said second catch (45) and said soldering tail (46) of each male terminal (39a, 39b). The electrical connector according to any of claims 3 to 5, characterized in that the housing (2) has an elongated terminal mount (60) in the space defined by said side walls (3, 4) and said end walls (61, 62), said elongated terminal mount (60) having a latch member (55) formed at an end (58 or 59) thereof adjacent one of said end walls (61 or 62), and the complementary housing (32) has a catch member (53) formed at an end thereof adjacent an end wall (56 or 57), thereby permitting the housing (2) and the complementary housing (32) to be locked when mated together. The electrical connector as set forth in any of claims 1 to 7, characterized in that said housing (2) includes a second recess (18') which is arranged adjacent said deflectable portion (10b) of said horizontal base (10) and opposite said contact beam (13) to permit deflection of said base (10) without engaging said housing (2). The electrical connector as set forth in claim 8, characterized in that said second recess (18') is a hole extending through said housing base (5) to facilitate supporting the terminal (9a, 9b) during an overmolding process. The electrical connector as set forth in any of claims 1 to 9, characterized in that said tail portion (16) is adapted for surface mount soldering to a surface of a circuit member and is generally parallel to said base member (10). The electrical connector as set forth in any of claims 1 to 10, characterized in that substantially all of said transition portion (15), with the exception of a portion adjacent said recess (19), is embedded within said housing.

Inventors: YAGI MASANORI, YAGI, MASANORI
Applicants: MOLEX INC, MOLEX INCORPORATED
Application year: 1994
Main classification: H01R12
IPC codes: H01R12